This invention relates to an apparatus and method for manipulating and anchoring cartilage and similar fibrous tissue within a joint.
Conventional medical clamps have certain disadvantages when used for manipulating cartilage or other tissue within a joint during arthroscopic surgery. Primarily, the clamps have a tendency to slip off the cartilage. Additionally, the size of the clamps in relation to the relatively small space within the joint makes it difficult to maneuver other surgical instruments, such as a scalpel or arthroscope, within the confined space of the joint. Such clamps can also interfere with the view of the inside of the joint afforded by the arthroscope. Since the clamps must be .introduced into the joint through an incision, they are limited in their range of manipulation by the location of the incision. In order to apply a desired directional traction to the cartilage, it may be necessary to release the clamp from the cartilage, reintroduce the clamp through another incision, and reclamp the cartilage.
It is often necessary to repair torn fibrous tissue, such as a ligament or tendon, or reattach such tissue to bone. While in some instances it is possible to insert two needles into the joint and then thread both of them with a suture to form a loop to reattach torn parts of fibrous tissue, that procedure is undesirable because it is complex and time-consuming. The alternative of more radical arthrotomy is also undesirable because of the increased amount of trauma and resultant increased morbidity encountered in the use of such a procedure.
As is explained in the following summary and description, the present invention provides a relatively compact and easy to use apparatus for manipulating cartilage and other fibrous tissue, and for anchoring the tissue to other tissue or to bone. Some technical references that may be of general interest are as follows: Allen, U.S. Pat. 3,699,969; Shein, U.S. Pat. 3,527,223; Woo, U.S. Pat. 3,943,932; Almen, U.S. Pat. 3,500,820; Johnson et al., U.S. Pat. 3,871,368; and Smith, U.S. Pat. 4,243,037. None of these references discloses a method or apparatus suitable for manipulating fibrous tissue during arthroscopic surgery, or for effectively reattaching fibrous tissue to bone or to other fibrous tissue.
The aforementioned problems associated with use of conventional medical clamps for manipulating tissue are overcome by the present invention, which provides an apparatus and an associated method for manipulating and anchoring tissue during arthroscopic surgery. The apparatus provides adequate fixation of the tissue during such surgery and minimally interferes with the use of other instruments within the joint.
The apparatus particularly comprises an elongated anchor member having a suture attached proximate the midpoint of its length. The anchor member is inserted through the tissue with the suture extending therefrom to provide a mechanism for manipulating the tissue within the joint. The end faces of the anchor member may be slanted to facilitate movement of the anchor member through the tissue.
The preferred means of inserting the anchor member includes a hollow needle having a sharp tip and an open butt. A hollow tube of equal or greater length than the needle slides within the needle. A limiting mechanism is provided at the butt of the needle and at the corresponding portion of the hollow tube to selectively position the tube within the needle so that the tube does not extend outwardly beyond the tip of the needle.
The anchor member is located within the tip of the hollow needle in either a deformed U shape, or in its normal, substantially straight shape. The suture extends from the anchor member through the bore of the tube.
A removable shield fits over the tip of the needle to prevent the sharp tip from cutting the suture or the anchor member during the process of inserting the anchor member into the hollow needle.
With the anchor member located within the tip of the needle, the needle tip is inserted into a joint during a surgical procedure. The needle tip pierces the tissue to be anchored and passes substantially through the tissue. The limiting mechanism is manipulated so that the tube may be pushed forward to the tip of the needle, thereby expelling the anchor member from the tip of the needle into or behind the piece of tissue to be anchored. As the anchor member is expelled from the tip of the needle it assumes an orientation generally perpendicular to the length of the suture. The needle and tube are then removed from the joint, leaving the suture extending through the tissue and out of the joint. The tissue is manipulated by the application of tension on the suture.
If it is desirable to push the tissue, the suture may be rethreaded or left threaded in the tube and the tissue may then be securely held between the tube and the anchor member by applying tension to the suture. If it is desirable to control the tissue from a different angle, or through a different incision, a hook-ended instrument may be passed through another incision to hook the suture and pull the tissue. It will be apparent that moving the tissue in this manner is possible without detaching the anchor member from the tissue. If necessary, the tissue may be removed from the joint by tension on the suture once the tissue has been surgically freed from the joint.
It is often desirable to permanently reattach to bone fibrous tissue, such as tendons or ligaments. An alternative embodiment of a tissue anchoring apparatus is provided for that purpose. More particularly, the apparatus of this embodiment includes a deformable anchor member that has a base and at least two legs. Each leg is attached to the base and extends therefrom to terminate in an outer end. A suture is attached to the base of the anchor member. The anchor member is formed of resilient material for urging the anchor member into a relaxed position wherein the ends of the legs are spaced apart a maximum distance. The anchor member is deformable into a deformed position wherein the ends of the legs are spaced apart a minimum distance that is less than the maximum distance.
While in the deformed position, the anchor member is insertable into a hole that is drilled into the bone at the location the tissue is to be attached to the bone. The hole has a diameter that is less than the maximum distance between the ends of the anchor member legs. Consequently, upon insertion of the anchor member into the hole, the ends of the anchor member legs bear, upon the bone within the hole, and the suture extends from the hole. Whenever tension is applied to the suture, the ends of the legs dig into the bone and resist removal of the anchor member from the hole.
With the anchor member anchored in the hole, the suture is available for securing the tissue to the bone. One way of using the suture to secure the tissue to the bone is to attach a retainer to the suture for pressing the tissue against the bone. The retainer includes resilient suture-engaging edges and corners, and is slidable along the suture in one direction, but grips the suture to resist sliding in the opposite direction. The retainer thereby holds tissue against the bone during healing so that the tissue will properly reattach to the bone.
To avoid prolonged irritation of surrounding tissues, the anchor member, suture, and retainer of the present invention may be made of material that is gradually absorbable by the body.